Process for forming welding protuberances on sheet metal, &amp;c.



E. KATZINGBR. PROCESS FOR FORMING WELDING PROTUBERANGES 0N SHEET METAL, &G.

APPLICATION IILBD MAYS, 1910.

1,005,9802- l Patented bof. 17, 1911.

iinrrnn strains rafrnivr onirica.

EDWARD KATZINGER, OF CHICAGO, ILLINCIS.

PROCESS FOR FORMING WELDING PROTUBRANCES ONVSHEET METAL, &c.

Specification of Letters Patent.

Patented Oct. 17,1911.

Application filed May 9, 1910. Seria-1 No. 560,102.

Io all whom t may concern:

Be it known that l, EuwAnoKA'rzrNonR, a citizen of the United States, residing at Chicago, in the county of Cook and State 5 of illinois, have invented certain new and useful Improvements in Processes for Fornv ing lVelding Froluberances on Sheet Metal and the Like. i i' This invention relates to a process 'for pre paring metals for being united by spot welding, and has for iis primary object 'to provide an improved process wherein,7 when a str ap or piece .of sheet metal is stamped to provide 'welding protuberances thereon, said strap or sheet will by said dies be lei't in a perfectly flat condition. g

Other and further objects will appear in the specification andbe more specifically pointed out in the appended claims, refering, whichl illustrates the several stepsfoi `the process. ,i

In the drawings- Figure i 1s a view nin elevation of cooperating dies by means of" which. the st ap or sheet metal is provided.-

lwith welding'protuberances- Fig. 2 isa similar view illustrating the iirst stage of the process in preparing a strip of metal for spot welding, parts being shownin section. Fig. 3 is a view similar to Fig3`2, illustrating a Afurtlgier stage of the process. Fig'. 4 is a View similar to Figs. and 3, showing the dies lat the end. oi the stal'nping opera` tion: F 5 is a side elevation of the strap provided with a plurality of welding protuberanees in the manner indicated in Figs. 2, 3 and 4. Fig. 6 is a top plan View oi' the strap shown in Fig. 5. According to present well known methods of spot welding, one of the/sheets may be provided with,I one or more protuberances which 'are pressed against the other sheet while a welding current is' being passed therethrough.` These protuberances can be most easily and rapidly 'formed between stamping dies but according to present well known methods the strip or sheet is bowed radially in all directions around each protuberance so that the sheet has imparted thereto a plurality of cup-shaped hollows. Moreover when a strap or bar is thus stamped, the bends in said bar corresponding to the locations of said bellows, cause the bar to assume an arcuate form. In coni sequence f these drawbacks, it becomes necessary to hammer the sheet or strap out flatl ence being had to the accompanying drawthe prot'uberance.

' before the welding takes place', an operation which consumes considerable time and eii'ort.

To provide stamping-dies of inlproved construction and conforination whereby the hand straightening or flattening operation isr g rendered unnecessary, constituteslfthe pri,- mary object oi: this invention."v By means of.,

the construction and yarraagement of parts in th'e pre" nt device, "however, a furti' beneficial `Aresult accrues"inthat` the o' scalesV which are usually found on them'eta s to be'welded are removed during' the stamp-` ing operation thus rendering unnecessary the usual pickhng bath with its attendantv expense and inconvenience.

In pursuanceoi'the objects and purposes of the present invention, means are 'provided 'for cupping the meta-l oppositely to the eup-` i ping which occurs 'during' the'formation of For `this purpose, stamp* ing dies l and 2 are made use of, the contiguously disposed endsl of the shank'p'orltions 3 and' lof lwhich are provided respec-` 'tively with a protuberance andrecess 615.0

proportioned and arranged as to form a protuberance l() on the inetal to be stamped, 'when theldies are moved together.

ln Fig. '2, is shown the form assumedl by the strap orbar 7' during the iirststage of' vtheoperation inwhichthe protuberance l0 `is `a}' nproximately completely formed and the bar on either side deflected upwardly into a position correspondingto that assumed by a `vbar after it has been operated upon by present well known types of stamping dies: y

The distinguishing features4 ot' the device forming' the subject matter of the present invention reside in and are connected with the provision atthe end of the male die of a cupped hollow 8 having a curvature correspending to the convex end 9 of the female die. In Fig. 3 is shown the relative positions of dies 1 and-2 corresponding to the final positions ofv dies commonly used. Should the bar 7 be removed at this stage of the operation, it. would assume a position approximately that shown in Fig. 2. stamping operation being continued, vhowever until the parts assume the positions shown in Fig. 4, the bar 7 upon being removed trom between the dies 1 and 2 assumes t-he straight flat position shown in Fig. 5, inasnulch as the degree ot' curvature imparted to the end faces ot' the dies l and 2 is 'just sufiicient to overcome the clipping which takes place during the first part of the process.

.In Fig. 5 is indie-ated the final position aspasses by successivey stages from the position shown in Fig. 2 to that shown in Fig. t, a complete' rearrangement of the surface molecules takes place with ,the result that the scales usually found on .the surface of the bar, are entirely removed .thus insuring a cleen Welding surface. l

ll. The process ofpreparing a. sheet for welding which consists in stamping said sheet to provide a'- Welding prctuherance thereon, and impressing the metal'of said sheet out of its plane 'on the'side of said protuberance to prevent said sheet from being cupped on the side opposite said protuberance, and finally in removing the pressure to permit the sheet to Hatten into a plone.

2. The process of stamping a met-el strap to form Welding protubera-nces thereon which consists in stamping the protubemnces on the strap during which operation said strap is cupped about each protuberance with said protuberance on the convex side, in supporting the metal of said strapimmediately contiguous to each protuberance, in pressing other portions of the metal surrounding the supported portions into cups with 'seid protuberances on the concave side, and finally in removing the pressure to permit the strep to straighten under the resiliency of the metal.

3. The process of preparing sheet metal for Welding which consists in stamping said sheet to form a Welding protuberance thereon during which operation the sheet is cupped 1n one direction with said pretuherance on vthe convex side, 1n flattening said sheet with the exception of said protuher-l in the same plone.

4. The process of forming protuberunces in sheet metal for Welding WhichV consists in stamping said sheet to provide e Welding projection, in clipping the metal conrexly with respect to the projection.v in continuing the stamping pressure in the seme direction to cup the metal in the reverse direction an amount suiiicient to overcome the lrst cupping action whereby when pressure is removed the metal sheet will assume e flat or plain condition.

5. The process of for-*ning projections in sheet metal Jfor spot Weiding which consists in stamping seid sheet to form a. protuberonce and cuppiug the mete? convexly on the side of the protuberance, in continuing the stamping pressure in the sume direction and cupping the metal concavely on the of the protuberzmce so that when the stamping pressure is removedthe metal sheet will lie Het and the protuberunce will project therefrom.

in testimony whereof have signed my name to this specification, in the presence of two subscribing Witnesses. on, this 2nd day of May AJD. 1910,

M. W. CANT-wenn A. O. Krimi-rr. 

